SQL & PL/SQL :: How Query Call Embedded Materialized View Automatically

I have to optimize the queries for user online panel. We have already created 2 materialized views:

mv_channel, mv_area

mv_channel (article_id, area, aweg_txt3, sum(value), sum(units))
mv_area (article_id, area, sum(value), sum(units))

For this query:

SELECT /*+ REWRITE*/
sum(value) as value,
sum(units) as unit,
article_id
from
...
where
...
and area in ('RB','RR','RS')
and aweg_txt3 n ('SB')
...

is the matview mv_channel very useful. The execution time was just 8s-13s instead fo 190s. But if the user also asks for this query but without AWEG_TXT3 in the where-clause, then it lasted 1:25min (longer than if the matview mv_area will be used).

The problem is that, the matview mv_area cannot be used in the case, in which the AWEG_TXT3 is in where clause (because it doesn't have aweg_txt3).

How can i do, so that :

- in case of AWEG_TXT3 in where-clause the matview mv_channel will be used and
- in another one (without AWEG_TXT3 in where-clause) the matview mv_area will be called automatically from the query